Charge forming device



April 25, 1933. F. E. ASELTINE CHARGE FORMING DEVICE Filed Nov. 2, 1929 2 Sheets-Sheet l 3 Fred 5. dselfz'ne April 25, 1933. F. E. ASELTINE' CHARGE FORMING DEVICE Fild Nov.

U M m. 0 2 M 0 2 a 2 m m 2 2 a 7 a 0 a Z Ma a M u% Patented Apr. 25, 1933 UNITED STATES PATENT OFFICE FRED E. ASELTINE, OF DAYTON, OHIO, ASSIGNOR TO DELCO PRODUCTS CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE CHARGE FORMING DEVICE Application filed November 2, 1929. Serial No. 404,322;

This invention relates to charge forming devices for internal combustion engines, and more particularly to devices of this character which comprise a plurality of primary carburetors, each of which delivers a primary mixture of fuel and air to one of a plurality of secondary mixing chambers located adjacent the engine intake ports and in which the primary mixture is mixed with additional air under certain operating conditions.

A device of this character is shownin the co-pending application of Fred E. Aseltine, Carl H. Kindl and Wm. G. Pontis Serial No. 360,404, filed May 4, 1929. The present invention is shown herein as embodied in a device of the construction shown in such ap plication and reference may be had thereto for a complete disclosure of the whole device.

It is the object of the present invention to 'provide means for securing equal distribution of the fuel charge to all of the individual cylinders of a multi-cylinder engine, and this object is accomplished by the provision of means connecting certain of the primary mixture conduits leading from the main carburetor unit to the secondary mixing chambers, with each other.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred embodlment of one form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a .front elevation of the manifold forming part of the charge forming device, said manifold being broken at the lines indicated.

Fig. 2 is a fragmentary plan view of said manifold.

' Fig. 3 is a vertical section through the manifold and main carburetor unit.

Fig. 4 is a detail section showing a fuel passage leading to certain of the fuel nozzles.

The manifold is indicated in its entirety by the reference numeral 10 and has three 50 outlet branches 12, 14 and 16, adapted to communicate with the intake ports of the engine when the device is assembled. Flanges 18 are provided. on the outlet branches for securing the device to the engine block in the usual manner, while a flange 20 is provided at the inlet end of the manifold to which the main carburetor unit is adapted to be secured.

. The carburetor unit comprises a housing 22 having afiange 24 adapted to be secured to'the flange 20 by screws 26. An air inlet coupling 28 is secured in an opening in the top of the housing in any suitable way and may be connected with an air cleaner if desired. A casting 30, in which the passages supplying fuel to the nozzles are formed, is secured in any desirable manner to the bottom of the housing 22 and a fuel bowl 32 is held tight against the bottom of said housing by any suitable means. Fuel is supplied to the bowl by means not shown, and a float 34 maintains a substantially constant level of. fuel therein in the usual way.

A pair of fuel nozzles 36 and 38 are provided in each primary mixing chamber 40, the structure of which is more fully described hereinafter. The nozzle 36 supplies all of the fuel at idling and relatively low speeds and a part of the fuel at all other times while the nozzle 38 is ineffective until the throttle has been opened a considerable distance and the engine is running at rela tively high speed. The two fuel nozzlesare supplied with fuel through separate fuel passages and the passage supplying the low speed nozzles is shown in Fig. 4. Fuel is admitted from the reservoir to a vertical passage 42 through a calibrated plug 44 screwed into the lower end of such passage, while at' its upper end the passage connects with a horizontal channel 46 communicating directly with all the low speed nozzles. The

passage supplying fuel to the high speed nozzles is not shown herein, nor the means for regulating the flow therethrough since this structure forms no part of this inven-. tion, but it is fully disclosed in the above mentioned application. Both high and low speed nozzles have restrictions 48 therein as shown in Fig. 2.

Each low speed fuel nozzle is provided with a main fuel outlet 50 in the topof the secondary outlets and fuel flows from the latter by action of gravity. The primary mixing chambers form the enlarged inlet ends of primary mixture passages 56 which are close together as shown in Fig. 4. And

- when the carburetor is secured to the maniearlier application.

I, held againsta seat 66 bya sprin fold these passages register with primary mixture conduits, which convey the primary mixture to the secondary mixing chambers as more fully described later. Restrictions 58 separate the mixing chambers from the remainder of the primary mixture passages,

and passages 59 admit. air immediately posterior to thenozzles to reduce the velocity of flow at the nozzles as fully set forth in the A sin 1e throttle valve 60, operated in a manner riefly described later, extends across all of the primary mixture passages to control the flow therethrough and is provided 1 with grooves 62 which register with the passages.

All of the air admitted to the carburetor is supplied through the coupling 28 and is controlled by a main air valve 64, normally 68, received between the valve and a ange projecting from a sleeve 72 'slidably mounted on a stationary sleeve 74, fixed in the main housing and guiding the air valve stem 76. In order to choke the carburetor to aid in starting, the valve may be lifted by means,

not shownv herein, until the-sleeve 72 engages the valve 64 to hold it closed. Enough air to carry the starting fuel to theintake ports is admitted through slots formed in the top of the air valve, as fully. shown in the earlier application. I I I The valve 64 admits air to a chamber 78 from which it flows to the primary mixing chambers through an opening 80 in the bot tom of the chamber and to the secondary mixing chambers through a passage 82, leading'to the manifold inlet, and controlled by manually and suction operated valves 84 and 86 secured to shafts 88 and 90 respectively, rotatably mounted in the main housing.

The operating means for the throttle and valve 84 form no part of this invention and are not described herein, but the mode of operation of these valves will now be very briefly set forth in order to enable a better understanding of the operation of the whole device. The throttle is connected to the valve 84 by an adjustable lost motion connection, which permits certain independent movement of the throttle and is generally adjusted so that the throttle may move independently'of the valve 84 until it reaches a position corresponding to a vehicular speed of approximately 15-20 miles per hour on a level. On further opening" of the throttle the valve 84 is moved simultaneously there-v 94 slidable therein and secured to the lower end of the air valve stem. The dashpot shown is filled with fuel by leakage around the piston, but any conventional form of dashpot may be employed.

The piston 96, normally held in position to close the port 98 by a spring 100, forms a relief valve to control the action of a dashpot for retarding the opening movements of the suction operated valve 90 while the passage indicated by the reference character 102 is one of the fuel inlets through which fuel is forced into the mixing chambers by a pump, operated on opening movements of the throttle. of the present invention and are not shown herein for the sake of simplifying the disclosure, but are fully shown and described in application 360,404.

The primary mixture passages 56 communicate, when the device is assembled, with conduits formed in the manifold. The middle one of these conduits comprises a straight passage 104 in'the manifold casting in which a tube 106 is received. This tube extends through the middle outlet branch of the manifold to supply primary mixture to thesecondary IIllXlIlg chamber in that particular branch, which supplies mixture to cylinders 3 and 4 of a. six cylinder engine. The two outside mixture passages 56 communicate with angular passages 108 and 109 in the manifold casting, which deliver primarymixture to pipes 110 and lllvconnected to elbows 112 and 113 secured to the end branches 12 and 16 of the manifold, and de-- livering primary mixtures. to tubes 116 which are fixed in branches 12 and 16.0f the manifold respectively, and deliver fuel -mixture to the secondary mixing chambers These devices form no part inders which fire between the firing of two cylinders communicating with any one intake port is not always the same. For exam 1c, the firing order of the Buick six cylinder engine is 1, 4, 2, 6, 3, 5. It will be obvious that the interval between the firing of cylinders 3 and 4 is always the same, butonly one cylinder fires between the firing of cylinders 1 and 2 and three cylinders fire between the firingof cylinders 2 and 1.

On the suct on stroke of the piston in any cylinder which precedes the firing of that cylinder there is a certain amount of suction created in the branches of the manifold which do-not communicate directly with the the cylinder on the suction stroke of the piston. Between the firing of cylinders Nos. 1 and 2, however, there will only be one suction stroke of the piston in some other cylinder, namely that in cylinder No. 4. It will be obvious, therefore, that unless some means be provided to prevent such action, there will be three times as much accumulation of fuel in the outlet branch of the manifold supplying mixture to cylinders 1 and 2 when the suction stroke of the piston in cylinder No. 1 takes place, as on the suction stroke of the piston in cylinder No. 2. This will result in supplying cylinder No. l with too rich a mixture and cylinder No. 2 with too lean a mixture. This is also true of cylinders 5 and 6, but not of 3 and 4 for obvious reasons.

According to the present invention this unequal distribution of the fuel is prevented by the provision of pipes connecting the primary mixture conduits, leading to outlet branches 12 and 16 of the manifold, to each other. A pipe 120 is connected in any suitable way-in the manifold casting so as to commun cate with the angular passage 108 immediately anterior to the bend therein, and its other end is connected to a curved plate 122 by brazing or in any other suitable manner,-while the plate is brazed or otherwise suitably secured to the tube 111, so that the pipe. 120 registers with-an orifice in said tube. A pipe 124 similarly connects the passage 109 with a tube 110.

By the provision of these pipes it will be clear that on the suction stroke of the pistons in each of cylinders 5 and 6a certain amount of suction is communicated to the passage 108 immediately in advance of the On each of these to the end of the primary mixture tube in branch 12 of the manifold so that there is practically no mixture drawn from the passage 108 into tube 111, the action being primarily the prevention of an accumulation of fuel in the branch 12 during the suction strokes of the pistons in cylinders 5 and 6 as heretofore described. In the same way the suction in the pipe 124 prevents an accumulation of fuel in the branch 16 of the manifold during the suction strokes of the pistons in cylinders 1 and 2, and in this manner the provision of these pipes brings about a substantially equal distribution of the fuel charge to all of the cylinders.

There is no suction communicated to the intake manifold except during the suction stroke of the piston in some cylinder of the engine when its intake valve is open. In the appended claims, suction during firing of certain cylinders is referred to in order to avoid confusionof language and it is to be understood that the term firing is to be construed broadly enough to cover the suction stroke of the piston in any cylinder as well as the actual firing thereof.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A charge forming device for multicylinder internal combustion engines comprising a. plurality of secondary mixing chambers communicating with different intake ports of said engine, primary mixture conduits supplying a primary mixture of fuel and air to said secondary mixing chambers, and means preventing the accumulation of fuel in any one of said secondary mixing chambers during the intake stroke of the piston in any engine cylinder not receivingcombustible mixture directly from that particular secondary mixing chamber, said means comprising means for communicating the engine suction to the primary mixture conduit delivering into said particular secondary mixing chamber at a point anterior to the outlet of said conduit.

2. A charge forming device for multicylinder internal combustion engines comprising a plurality of secondary mixing chambers communicating with different intake ports of said engine, primary mixture conduits supplying a primary mixture of fuel and air to said secondary mixing chambers, and means preventing the accumulation of fuel in an one of said secondary mixing chambers uring the intake stroke of the piston in any engine cylinder not receiving combustible mixture directly from that particular secondary mixing chamber, said means comprising a suction passage connecting the primary mixture conduit delivering into said particular secondary mixing chamber with the primary mixture conduit delivering into the secondary mixing chamber which connnunicatesdirectly with that cylinder in whichthe piston is making its intake stroke.

3. A charge forming device for a multicylinder engine comprising a plurality of secondary mixing chambers communicating with the engine intake ports, a plurality of primary mixture conduits delivering a primary mixture of fuel and air thereto, a plurality of primary mixing chambers supplying mixture to said conduits, means for supplying fuel and air thereto, and suction passages connecting certain of said primary mixture conduits with each other, whereby substantially equal distribution of the fuel charge to the engine cylinders is effected.

4. A charge forming device for a multicylinder engine comprising a plurality of secondary mixing chambers communicating with 'the engine intake ports,'a plurality of primary mixture conduits delivering a primary mixture of fuel and air thereto, a plurality of primary mixing chambers supplying mixture to said conduits, means for supplying fuel and air thereto, and suction passages connected with certain of said primary mixture conduits at a point near their inlet ends and with other of said conduits at a point nearer their outlet ends.

5. A charge forming device for a multicylinder engine comprising a plurality of secondary mixing chambers communicating with the engine intake ports, a plurality of primary mixture conduits delivering a primary mixture of fuel and air thereto, a plurality of primary mixing chambers supplying mixture to said conduits, means for supplying fuel and air thereto, bends in certain of said mixture conduits, and suction passages connected with certain of said primary mixture conduits at a point anterior to the bends therein and with other of said conduits posterior to said bends. 4

6. A charge forming device for a multicylinder engine comprising a plurality of secondary mixing chambers communicating with the engine intake ports, a plurality of primary mixture conduits delivering a primary mixture of fuel and air thereto, a plurality of primary mixing chambers supplying mixture to said conduits, means for supplying fuel and air thereto, bends in certain of said mixture conduits, and suction passages connected with certain of said primary mixture conduits at a point anterior and immediately adjacent to the bend therein and with other of said conduits posprimary mixture of fuel and air to one of said secondary mixing chambers and means for preventmg a flow of primary mlxture from a primary mixture conduit into its associated secondary mixing chamber during suction stroke of the piston in an engine cylinder not supplied with mixture directly by that particular secondary mixing chamber.

8. A charge forming device for a multicylinder internal combustion engine comprising a plurality of secondary mixing chambers communicating with difierent engine intake ports, a pluarlity of primary mixture conduits each of which delivers a primary mixture of fuel and air to one of said secondary mixing chambers and means for preventing a flow of primary mixture from a primary mixture conduit into its associated secondary mixing chamber during the suction stroke of the piston in an engine cylinder not supplied with mixture directly by that" particular secondary mixin chamber, said means comprising means or communicating to said primary mixture conduit at a point anterior to its delivery end a suction substantially equal to or greater than that maintained in its associated secondary mixing chamber.

which communicates with two engine cylinders, comprising a pluralityof secondary mixing chambers, one for each intake port, a plurality of primary mixture conduits each of which supplies a primary mixture of fuel and air to one of said secondary 'mixing chambers and means for preventing an accumulation of fuel in the secondary mixing chamber associated with any one of said intake ports during the suction stroke of the piston in any one of the cylinders not receiving combustible mixture from that particular intake port.

10. In a charge forming device for a six cylinder engine having three intake ports which communicate with cylinders one and two, three and four, five and six, respectively; a plurality of secondary mixing chambers one for each intake port, a plurality of primary mixture conduits, each of which supplies a primary mixture of fuel. and air' to one of said secondary mixing chambers, and means for preventing a flow of fuel from the primary mixture conduit supplying mixture to cylinders one and two during the firing of cylinders five and six, and vice versa.

11. In a charge formin device for a six cylinder engine having three intake ports which communicate with cylinders one and two three and four, five and six, respectivel a plurality of secondary mixing chambers, one-for each intake port, a plurality of primary mixture conduits each of which supplies a primary mixture of fuel and air to one of said secondary mixing chambers, and a suction passage connecting the primary mixture conduit supplying primary mixture to cylinders one and two with the conduit supplying primary mixture to cylinders five and six.

12. In a charge forming device for a six cylinder engine having three intake ports which communicate with cylinders one and two, three and four, five and six, respectively; a plurality of secondary mixing chambers one for each intake port, a plural- .ity of primary mixture conduits each of which supplies a primary mixture of fuel and air to one of said secondary mixing chambers, and suction passages connecting the inlet ends of the conduits supplying primary mixture to cylinders one and two and five and six, with the conduits supplying primary mixture to cylinders five and six and one and two respectively. p

13. An intake manifold for a multi-cylinder internal combustion engine comprising a plurality of outlet branches adapted to communicate with the engine intake ports, an air inlet supplying air to said branches, primary mixture conduits in said manifold adapted to deliver a primary mixture of fuel and air to said branches and suction passages connecting certain of said primary mixture conduits. with each other.

In testimony whereof I hereto aflix my signature.

FRED E. ASELTINE. 

